mm/mmzone.c

   1 /*
   2  * linux/mm/mmzone.c
   3  *
   4  * management codes for pgdats and zones.
   5  */
   6
   7
   8 #include <linux/stddef.h>
   9 #include <linux/mmzone.h>
  10 #include <linux/module.h>
  11
  12 struct pglist_data *first_online_pgdat(void)
  13 {
  14         return NODE_DATA(first_online_node);
  15 }
  16
  17 EXPORT_SYMBOL(first_online_pgdat);
  18
  19 struct pglist_data *next_online_pgdat(struct pglist_data *pgdat)
  20 {
  21         int nid = next_online_node(pgdat->node_id);
  22
  23         if (nid == MAX_NUMNODES)
  24                 return NULL;
  25         return NODE_DATA(nid);
  26 }
  27 EXPORT_SYMBOL(next_online_pgdat);
  28
  29
  30 /*
  31  * next_zone - helper magic for for_each_zone()
  32  */
  33 struct zone *next_zone(struct zone *zone)
  34 {
  35         pg_data_t *pgdat = zone->zone_pgdat;
  36
  37         if (zone < pgdat->node_zones + MAX_NR_ZONES - 1)
  38                 zone++;
  39         else {
  40                 pgdat = next_online_pgdat(pgdat);
  41                 if (pgdat)
  42                         zone = pgdat->node_zones;
  43                 else
  44                         zone = NULL;
  45         }
  46         return zone;
  47 }
  48 EXPORT_SYMBOL(next_zone);
  49